1. Field of the Invention
The present invention relates to compositions comprising a therapeutically effective amount of genetically modified cells containing a genetic construct expressing a TGFβ inhibitor effective to reduce expression of TGFβ, where the genetically modified cells are non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC) cells, and related methods.
2. Description of the Related Art
Lung cancer remains the most prevalent cancer in the western world, accounting for 30% of all cancer-related deaths (Ramanathan and Belani, 1997). The current prognosis for patients with lung cancer is poor. The overall cure rate is estimated as low as 13%. Approximately 180,000 new cases of lung cancer are expected in the United States in 1999. The majority of these patients will die of their disease with 160,000 deaths from lung cancer expected nation-wide in 1999.
There are two major subdivisions of lung cancer: 1) non-small cell (NSCLC) and 2) small cell lung cancer (SCLC). Treatment approaches and natural history differ for these two diseases. The majority (80%) of cases of lung cancer in the United States are NSCLC. Although advances in the understanding of important clinical and prognostic factors for both NSCLC and SCLC have been made in the past 20 years, there have been minimal improvements in therapeutic results. The only curative option for patients with NSCLC is local therapy (surgical excision or local irradiation) in patients with early stage disease (I & II) when the tumor is still localized. At diagnosis however, the majority of patients with NSCLC present with advanced disease, which is not curable by surgery alone. In advanced stages of disease, systemic chemotherapy and/or irradiation can produce objective responses and palliation of symptoms, however, they offer only modest improvements in survival. The median survival of patients with non-resectable disease is 6-12 months. Two-year survival rates for stages IIIB and IV NSCLC are 10.8 and 5.4 percent respectively. Likewise, five-year survival rates are 3.9 and 1.3 percent. Recently, several new drugs have become available for the treatment of NSCLC including paclitaxel (Taxol), docetaxel (Taxotere), topotecan, irinotecan, vinorelbine, and gemcitabine. While these drugs are improvements over prior chemotherapeutic agents (etoposide, cisplatin and carboplatin), the overall cure rate remains low.
SCLC is a very aggressive cancer which metastasizes early and often, and it has a median survival from diagnosis of only two to four months. Localized forms of treatment, such as surgical resection or radiation therapy, rarely produce long-term survival because of this cancer's propensity for distant metastasis. With chemotherapy, survival can be prolonged at least four to five times the media survival rate for patients who are given no therapy, however the overall survival at five years remains at only 5-10%.
Since current therapeutic modalities do not significantly enhance life expectancy in stages of NSCLC or SCLC patients, exploration of new therapeutic approaches for these patients is justified.